Readers respond; automating anemia assay.The article by Dr. Vijay Kumar entitled "Pernicious anemia" in the February 2007 issue of MLO MLO Mycoplasma-like organism(s) [p. 28], provided an excellent summary of this autoimmune disorder. Detecting the presence of intrinsic factor autoantibodies in patients with vitamin B12 deficiency vitamin B12 deficiency Megalobalstic anemia, see there is considered fairly diagnostic of chronic gastritis and pernicious anemia (1) as it is rare to find intrinsic factor antibodies associated with other conditions (2). Traditionally, a Schilling test is considered confirmatory of vitamin B12 deficiency, which demonstrates poor ability of the intestine to absorb vitamin B12. However, the Schilling test is expensive, laborious, and uses a radioisotope radioisotope: see radioactive isotope. Radioisotope (biology) A radioactive isotope used in studying living systems, such as in the investigation of metabolic processes. . The author states that radioimmunoas-says (RIA (Rich Internet Application) A Web-based application that approaches the speed and elegance of a local application. An RIA may refer to a browser-based application that uses AJAX or another enhanced coding technique. ) and enzyme linked immunosorbent immunosorbent /im·mu·no·sor·bent/ (-sor´bent) an insoluble support for antigen or antibody used to absorb homologous antibodies or antigens, respectively, from a mixture; the antibodies or antigens so removed may then be eluted in pure assays (ELISA ELISA (e-li´sah) Enzyme-Linked Immuno-Sorbent Assay; any enzyme immunoassay using an enzyme-labeled immunoreactant and an immunosorbent. ELISA n. ) can be used for the detection of antibodies to intrinsic factor. These tests are often batched and have a slow turnaround time dependent on laboratory workload. [ILLUSTRATION OMITTED] In addition to the commercial RIA and ELISA kits currently available, Beckman Coulter offers a rapid, automated immunoassay for detecting intrinsic-factor antibodies that can be used in conjunction with vitamin B12 on the family of access immunoassay systems. The intrinsic-factor-antibody assay is a competitive-binding immunoenzymatic assay for the detection of intrinsic-factor antibodies. The assay uses single-point calibration that is stable for 14 days. Time to first result produced from serum or heparinized plasma is 35 minutes. Although intrinsic-factor-antibody testing may not be required on an urgent basis within the healthcare setting, automation of this testing method provides the laboratory the flexibility to perform reflex intrinsic-factor-antibody testing following vitamin B12 testing. Since pernicious anemia is an autoimmune condition, it is important to establish a diagnosis as patients with this condition have a higher incidence of developing other autoimmune syndromes and have an increased incidence of gastric cancer. (1), (2) References (1.) Toh BH, vanDriel IR, Gleeson PA. Pernicious anemia. NEJM NEJM New England Journal of Medicine . 1997;337(20):1441-1448. (2.) Day P. Intrinsic factor antibody testing, automated diagnosis of pernicious anemia. The Biomedical Scientist. 2006:877-879. --Lori Rusch, PhD, MT(ASCP ASCP American Society of Clinical Pathologists. ) Staff Applications Scientist Immunodiagnostics Business Center Beckman Coulter Inc. Chaska, MN MLO welcomes letters to the editor. We ask that you include a phone number for verification. While we prefer to publish the writer's name, we will publish a letter with "name withheld by request," but our editorial staff must have the writer's name confirmed for our files. MLO reserves the right to edit any letter for style and length. |
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